'90 300E heat problem

Especially in the summer time, when i drive my car and then turn it off, it then builds up a lot of heat within the engine while i am parked before it cools down, so much so that sometimes the A/C compressor does not engage if the temp is too high if restarted shortly after. When i do start the car, it does cool down immediately to normal temperatures. Is there a problem or is this normal? I am worried about excessive engine wear due to heat while it sits parked....Newer cars have fans that run for a while after the engine is shut off. Is there some way to get my Mercedes to do this? Thanks - Mike

[PaulG]

Yes, it's very easy to fit a fan that will run after the engine's switched off. This will certainly help with your static overheating problem.

In the UK they're made by Kenlow and sell for about 90m quid, but I don't know if they're available across the pond.

A side advantage is that they can be set to cut-in at any temperature, so you can run the engine cooler and make things easier when you stop.

Any electric fan and temperature switch from a breakers yard can be made to do the job you need, but it will need a bit of "hands-on" inginuity to make it fit......

Hi,

Probably no need to worry.

The oil is still at the top of the motor and starts to drain when it is is shut off. The oil will take care of the heat.

The water temp does go higher but that's not really a problem as long as the cooling system is in good shape.

Generally, in hot months before shutting the engine off, I will rev the motor to about 1500 to 2000 RPMs to engage the larger cooling fan and get the water pump moving more coolant. I'll do this for about 15 seconds and then let it come back to idle before shutting off.

BTW: Don't do this if you have a turbocharger. Just let the car idle for 15 to 30 seconds.

Regards,

[300E24V]

I have the m104 engine and it has an auxilary water pump that keeps the water circulating for up to 10 mins after the car is swithched off.
It is located just below the windscreen washer container that holds the water.
Check if you have it,you should.

[anthonyb]

You might be able to save a little bit of wear on your engine (actually, probably more like the head gasket and hoses, not the engine itself, since the parts aren't moving), but I don't think this should be much of a problem. The heat source is the combustion process, and once you shut off the ignition, the engine stops producing heat. I suppose you could argue that the lack of water circulation would impair the ability of the block to dissipate heat, but there should be plenty of reserve heat sink capacity in the coolant to keep the block well within tolerances.

If the engine is designed to operate at temperatures between 100 and 110, when heat is constantly being added to the system, I suspect it will be just fine when the coolant temperature is at 110 and no additional heat is entering the equation.

My $0.02..

anthony

[anthonyb]

p.s. if you're still concerned, a free easy way to deal with the overheat problem is just to open the hood after you shut off the car. This'll help dump LOTS of underhood heat, though the one drawback is you probably can't do it outside of your home.

I found the aux. water pump, but I guess I never thought to see if it was still working or not, plus I did not know what it was specifically for. Is there any way to tell if it is still operating and when it is suppost to turn on? That is a really neat feature as opposed to an electric fan that keeps running after the car is shut off. -- Mike

[anthonyb]

Aux water pump assists water flow through the heater core. You can tell if it's working by switching the climate control on "heat" or "defrost" and checking the pump for light vibration or buzzing.

-anthony